Crane for wind turbine blade assembly, a vessel, a hoisting method, and an assembly method

Abstract

A crane includes a crane structure defining a substantially vertical rotation axis; a boom connected with a first end to the crane structure to be rotatable about the vertical rotation axis; a trolley moveable along the boom in longitudinal direction of the boom; a hoisting cable and a load connector. The load connector is arranged at a free end of the hoisting cable to be connected to a load for hoisting purposes. The trolley includes a cable guide to guide the hoisting cable and an attachment configured to temporarily attach the load connector to the trolley to fix the position of the load connector relative to the trolley.

The invention claimed is: 
     
       1. A crane configured for hoisting a wind turbine blade held in a horizontal orientation in a frame during the hoisting, the crane comprising:
 a crane structure defining a substantially vertical rotation axis; 
 a boom connected with a first end thereof to the crane structure so as to be rotatable about said vertical rotation axis along with the crane structure; 
 a trolley that is mounted moveable along the boom in a longitudinal direction of the boom; 
 a hoisting cable; and 
 a load connector, 
 wherein the load connector is arranged at a free end of the hoisting cable and is configured to be connected to a frame holding a wind turbine blade held in a horizontal orientation in a frame during hoisting, 
 wherein the trolley comprises:
 a cable guide configured to guide the hoisting cable; and 
 an attachment configured to temporarily attach the load connector to the trolley in order to fix a position of the load connector relative to the trolley; wherein the load connector comprises a sheave block, and wherein the attachment forms a cavity in which the sheave block is received upon hauling in the hoisting cable. 
 
 
     
     
       2. The crane according to  claim 1 , wherein the crane comprises holding support cables configured to connect the load connector to the frame holding a wind turbine blade. 
     
     
       3. The crane according to  claim 1 , wherein a hoisting plane is defined by said vertical rotation axis and the boom, and wherein the cable guide of the trolley, the hoisting cable, and the load connector are all arranged in said hoisting plane. 
     
     
       4. The crane according to  claim 3 , wherein the crane comprises a first pair of tugger lines, said first pair of tugger lines being configured to position the frame holding a wind turbine blade in a rotational direction about a horizontal axis which extends in said hoisting plane that is defined by the vertical rotation axis and the boom. 
     
     
       5. The crane according to  claim 4 , wherein the first pair of tugger lines are arranged to extend between the boom at a location above the trolley and the frame holding a wind turbine blade on either side of said hoisting plane. 
     
     
       6. The crane according to  claim 4 , further comprising a second pair of tugger lines, said second pair of tugger lines being configured to position the frame holding a wind turbine blade in a rotational direction about a vertical axis which extends in said hoisting plane that is defined by the vertical rotation axis and the boom. 
     
     
       7. The crane according to  claim 6 , wherein the second pair of tugger lines are arranged to extend between the trolley and the frame holding a wind turbine blade on either side of said hoisting plane. 
     
     
       8. The crane according to  claim 1 , wherein the hoisting cable runs from a fixed location at a free end of the boom downwards towards the cable guide on the trolley. 
     
     
       9. The crane according to  claim 1 , wherein the hoisting cable is permanently provided from the trolley towards the cable guide. 
     
     
       10. The crane according to  claim 1 , the crane further comprising a frame configured to hold a wind turbine blade in a horizontal orientation during hoisting. 
     
     
       11. The crane according to  claim 10 , wherein the frame comprises a clamping mechanism configured to fix the wind turbine blade relative to the frame and a power unit to power the clamping mechanism. 
     
     
       12. A vessel comprising the crane according to  claim 1 . 
     
     
       13. A method for hoisting a wind turbine blade held in a horizontal orientation in a frame during the hoisting, wherein the method makes use of the crane according to  claim 1 , wherein the method comprises:
 arranging the hoisting cable such that the hoisting cable is guided by the cable guide on the trolley; 
 positioning the trolley over the frame holding a wind turbine blade in a horizontal orientation; 
 connecting the frame to the load connector; and 
 lifting the frame and the wind turbine blade held in a horizontal orientation. 
 
     
     
       14. The crane according to  claim 1 , wherein the crane comprises holding support cables configured to connect the load connector to the frame holding a wind turbine blade.